1. Field of the Invention
This present invention is directed to blowout preventers, to bonnets and ram blocks for them, and, in certain particular aspects, to pivotal ram block supports, and methods of their use.
2. Description of Related Art
The prior art discloses a wide variety of blowout preventers and blowout preventer bonnets.
Typical blowout preventers have selectively actuatable rams in oppositely disposed bonnets secured to the body which, in certain prior art systems, are movably secured with movable bars or with hinges and bolts so that the bonnet is movable for access and maintenance. The rams are either pipe rams (to contact, engage, and encompass pipe and/or tools to seal a wellbore) or shear rams (to contact and physically shear a pipe or tool in a wellbore). Rams are usually positioned opposite each other on either side of a main body and can seal against each other at a center of the main body over a center of a wellbore.
Typical rams include a ram block on which parts, e.g. seals and/or cutting blades, are releasably secured. Such seals can be subject to high pressures and to chemical reaction with drilling fluids which can damage the seals. Often rams are inspected or changed out. Prior art systems include a variety of movable bonnets for accessing rams and seals. Blowout preventers are disclosed in many U.S. Patents, including, but not limited to, U.S. Pat. Nos. 3,946,806; 4,043,389; 4,313,496; 4,132,267, 4,558,842; 4,969,390; 4,492,359; 4,504,037; 2,752,119; 3,272,222; 3,744,749; 4,253,638; 4,523,639; 5,025,708; 5,056,418; 5,400,857; 5,575,452; 5,655,745; and 5,918,851.
There has long been a need, recognized by the present inventors for a blowout preventer with easy access to a ram block in a bonnet and for easily moving such a ram block to a position at which it can be inspected and/or replaced.
There has long been a need, recognized by the present inventor for easy access to sets of rams (lower and/or upper) of a blowout preventer.